Bleeding gums in 9 month old (prob massively pfb)

[lobsters]

I've just brushed DD's teeth before bed and noticed afterwards there was a little bit of blood in her saliva around her mouth. I tried to look in her mouth, but couldn't see an obvious source, but she was screaming blue murder so not easily look particularly at bottom teeth. She's always hated having her teeth brushed, so the screaming wasn't anything new, but I'm now wondering if anything is wrong. Her 4th tooth has just come through and no more look imminent, so I'm not sure what's going on.

Anyone know if it's something I need to get checked out or just somehing that is likely to happend at this age with general teething etc? I'll have another look in the morning when after teeth brushing again.

Is it possible that she may have banged her chin?
My DS currently has 5 teeth, 2 at the bottom and 3 on top.
Often when he bangs his chin, his bottom teeth go up into the roof of his mouth, causing him to bleed. His problem is that he is yet to get any molars to keep his mouth in the proper position.
I wonder if your DD may have the same problem.